This research will be done primarily in Uruguay at Montevideo University in collaboration with Bruce A. Freeman as an extension of NIH grant # R01 HL058115. The experimental goals described in this new FIRCA application serve to expand the mutually beneficial collaborative research and training endeavors related to inflammatory signaling and tissue injury mechanisms being jointly conducted by investigators at the UAB School of Medicine and the Facultad de Medicina of the Universidad de la Republica in Montevideo, Uruguay. Drs. Freeman and Rubbo have collaborated since 1993, when Dr. Rubbo conducted PhD dissertation and postgraduate research studies at UAB. In the new research plan proposed for FIRCA support, the theme of the parent grant -that reactions between -NO-derived species and target molecules form bioactive nitrogen-containing lipid adducts - will be expanded in a new and important direction. The foreign collaborators will address the novel concept that nitrated lipids (in particular cholesteryl-nitrolinoleate) can exert unique anti-inflammatory signaling actions by counter-balancing oxidative processes. We select the monocyte/macrophage model that represent a critical factor in the initiation and evolution of the inflammatory response. It is hypothesized that early inflammatory oxidant response to acute inflammation create an inflammatory milieu that promotes the generation of secondary nitrated lipid mediators that in turn serve to "reprogram" tissue gene expression and metabolic responses of macrophages towards an anti- inflammatory phenotype that facilitates resolution of inflammation. To address these concepts, two key experimental aims will be pursued. We will: 1. Characterize the major nitrated derivatives of cholesteryl linoleate in human plasma, LDL and activated macrophages as well as the mechanisms of formation. 2. Evaluate the capacity of cholesteryl-nitrolinoleate to modulate macrophage differentiation towards an anti- inflammatory phenotype. Successful accomplishment of the proposed aims will develop and solidify the concept that reactions between -NO -derived species and oxidized lipids mitigate pathologic events, often by forming unique nitrogen-containing adducts of unsaturated fatty acid (linoleate)-containing cholesterol. [unreadable] [unreadable]